The maintenance of an SSD-intensive datacenter can be costly. Various total cost of ownership (TCO) models have been proposed to evaluate and assess storage subsystem solutions. However, there is no standard formula for calculating the TCO of the SSD-intensive storage subsystem. In order to comprehensively access the expenditure of a datacenter, a TCO model should account for purchasing and maintenance costs, service times, served I/O amount and device wearout.
Sequentiality of writes in input/output (I/O) operations has a big impact on write amplification of solid-state drives (SSDs). Increased randomness in a write stream increases the write amplification of the SSDs. Since SSDs have limited write (erase) cycles, a higher WAF caused by randomness in a write stream can shorten the lifetime of the SSDs and thus increase the TCO of a datacenter.
Write amplification affects the limited lifecycle of SSDs. For example, workload patterns with different sequential ratios can vary write amplification even on the same SSD. The varying write amplification caused by different sequential ratios can change the lifetime of the device eventually affecting the TCO. Therefore, there is a need to evaluate storage systems from a cost perspective including diverse dimensions such as maintenance and purchase cost, device wearout, workload characteristics, and total data amount that can be written to the disk.